The Expression of L-type Calcium Channel mRNA by the Concentrations of Glucose on the Cell Proliferation in Cultured OLETF Rat Aortic Vascular Smooth Muscle Cells

ABSTRACT

BACKGROUND: The proliferation of vascular smooth muscle cell(VSMC) is a part of the major pathogenic mechanism for atheroscle- rosis. It has been reported that L-type calcium channel plays a role in the VSMC proliferation in diabetic rats. But there is a little study results about the association between L-type calcium channel and VSMC proliferation by glucose concentrations in culture media. So we examined the association between voltage-dependent L-type calcium channel of VSMCs and the proliferative activity of vascular smooth muscle cells. METHODS: Rat aortic VSMCs were isolated from the aorta of OLETF rat by enzyme method. VSMCs were cultured in various concentrations of glucose(5.5, 25 mM). The VSMCs(1x104 cells in 24-well plates) were incubated in the presence of Bay K 8644 (10-6M) with/without verapamil(10-6M) for 48 hours. Then the proliferation was assessed by MTT(methylthiazole tetrazolium) assay and expression of L-type calcium channel mRNA was measured by RT-PCR. RESULTS: The proliferative ability and the expression of L-type calcium channel of cultured VSMCs were increased dose-dependently by the glucose concentrations(p<0.05). Bay K 8644 enhanced the proliferation of VSMC and verapamil blocked the incremental effects induced by Bay K 8644. CONCLUSION: These results suggest that L-type calcium channel may play a role in VSMC proliferation of OLETF rat.